JSFiddle - React, Tailwind, and code Playground
HTML
<canvas id="myCanvas" width="500" height="500"></canvas>
JavaScript
function RingBuffer(length) {
this.length = length;
this.pointer = 0;
this.buffer = [];
}
RingBuffer.prototype.get = function(index) {
if (index < 0) {
index += this.length;
}
return this.buffer[index];
}
RingBuffer.prototype.push = function(value) {
this.buffer[this.pointer] = value;
this.pointer = (this.length + this.pointer +1) % this.length;
}
var c = document.getElementById("myCanvas");
var context =c.getContext("2d");
timer = window.setInterval(draw_line, 30);
function Point(x,y) {
this.x = x;
this.y = y;
}
Point.prototype.translateX = function(x) {
return this.x += x;
};
Point.prototype.translateY = function(y) {
return this.y += y;
};
function draw_line()
{
context.fillStyle = "#000";
context.fillRect(0, 0, c.width, c.height);
var pointer = history.pointer;
context.beginPath();
context.lineWidth = 2;
context.lineJoin = "round";
context.strokeStyle = '#F00';
var p1 = history.get(--pointer);
if (p1) {
context.moveTo(p1.x, p1.y);
for (iteration = 0, count = 15; iteration < count; iteration += 3) {
var p2 = history.get(--pointer);
var p3 = history.get(--pointer);
var p4 = history.get(--pointer);
if (p1 && p2 && p3 && p4) {
context.bezierCurveTo(p2.x, p2.y, p3.x, p3.y, p4.x, p4.y);
}
p1 = p4;
}
}
context.stroke();
context.closePath();
}
var history = new RingBuffer(16);
var lastGrab = new Date();
c.addEventListener('mousemove', function() {
now = new Date();
if (now - lastGrab > 15) {
history.push(new Point(event.clientX - c.offsetLeft, event.clientY - c.offsetTop));
lastGrab = now;
}
});